This invention relates to a roof drilling and bolting device for use in placing roof bolts in the roof of mine passageways. In particular, it relates to a roof drilling and bolting device of the type described in our U.S. Pat Application Ser. No. 030,219 filed Apr. 16, 1979 entitled "Roof Bolting Device." In particular, this invention relates to a drill guide for supporting the drill steel as it is started into the mine roof and moved therein. In the apparatus according to our above referenced patent application, the drill steel is inserted in the chuck of a drill pod, which is a hydraulic motor for turning the drill steel, and the drill pod is moved vertically upward along a generally vertical track. The track is mounted on or comprises part of a generally vertical tower. The tower itself is arranged for movement over a horizontal rail thus resulting in rectilinear positioning of the drill pod.
It is an advantage of this invention to provide a drill steel guide mounted near the top of the tower, which guide can be kicked out of the path of the drill pod as it is raised past the vertical position where the guide is mounted. It is a further advantage that the coal dust ever present in the environment in which the drill steel guide is mounted will not accumulate and clog the workings of the guide.
Briefly according to this invention, there is provided a drill steel guide for mine roof drilling and bolting machines of the type in which a drill pod is raised and lowered along a generally vertical track. The drill steel guide is mounted relative to the vertical track spaced from the downwardmost position of the drill pod. Typically the drill steel guide is mounted near the top of the tower which guides the vertical track which in turn guides the vertical movement of the drill pod. In any event, the drill guide is mounted at a location downward from the upwardmost travel of the drill pod. The drill steel guide according to this invention comprises a main shaft mounted on a generally horizontal axis relative to the vertical track. Pivotally mounted to the main shaft is a clevis body. The clevis body is swingable from a generally horizontal to a generally vertical position upon the main shaft. A stop fixed relative to the shaft limits the downward swing of the clevis body at the generally horizontal position. A spring latch holds the clevis body in its generally vertical position until it is pulled down by hand pressure. The spring latch comprises a spring biased plunger which is guided by a bore in the clevis body and bears upon a cam surface on the main shaft.
Two retaining arms are pivotally mounted to said clevis body on separate axles fixed in the clevis body which axles are perpendicular to the main shaft and generally parallel to the drill steel when the clevis body is resting on the stop. The retaining arms together define a drill steel guide passage for receiving and guiding the drill steel. Springs secured to the clevis body bias the retaining arms together. To lock the retaining arms about the drill steel in their drill steel guiding position, there is provided a palm lock which comprises a shaft journaled in the clevis body in bores having an axis parallel to the retaining arm axles. The palm lock carries extensions for embracing the retaining arms. In one position, the palm lock carries the extensions into the embracing position locking the retaining arms against rotation away from the drill steel. In another position, the palm lock carries the extensions free of and away from the retaining arms. A spring plunger mounted in the clevis body latches the palm lock so that in either of its positions, it does not tend to drift toward the other position. An extension of the palm lock shaft is arranged to be aligned with a kick plate or the like attached to the drill pod such that as the drill pod approaches the guide, the kick plate moves the palm lock to its nonlocking position. This enables the retaining arms to be spread and therefore the drill pod can kick the entire clevis body out of its path of travel.